| At present, P2P has already become Internet bandwidth murderer. Statistics indicate, in the P2P network, there are only few nodes located in the identical autonomous system, large mount of inter-domain traffic will be generated, which brings enormous capacity pressure into the backbone network. As a result, it is difficult for the service providers to keep the design strategy of"sacrificing bandwidth to get the quality of service". On the other hand, with the improvement of P2P technology and new software development, the existing content buffering system does not work well in the P2P network, in particular under complex DHT multi-domain environment. How to solve content buffering problem under the DHT environment is a hot topic in the current P2P network researching area.The main work done of this dissertation is:①. The features of DHT multi-domain network is analysed in this dissertation, then a new model used to recognize traffic of DHT node is proposed.Based on the traditional application payload recognition foundation, a modified AC_BM algorithm and SPUA algorithm (Statistical Probability Protocol Priority Unrelated Algorithm) are used to identify DHT flows and the info_hash strings of files which downloading by local user. Accurately effective DHT traffic from BT downloading traffic re-identified by using the P2P connection characteristic feature, which is the P2P communication simultaneously has TCP and UDP traffic, and the statistics characteristics show difference of host IP and PORT paires number very small. The algorithm structure of identifying model is given in this dissertation, and the performance analysis is also made.②. In order to solve the problem of unknown BT traffic which grows unceasingly, a TCP flow control method based on TSW (Time Sliding Window) model is proposed in this dissertation, this mechanism is achieved by the bypass blocking, this model was composed by a rate estimator, a marker and a blocking maker three function parts.The appropriate value of time windows in rate estimator is determined through lots of experiments and theoretical analysis; and one kind of effective dencity-aware separate algorithm for connection blocking is proposed. In addition, the method mechanism to block the traffic effectively is discussed in this dissertation. The blocking mechanism can provide good realization of dynamic and precised application protocol traffic control by the experimental system confirmation. ③. Based on above research foundation, a kind of DHT node multi-domain cache system model is proposed in this dissertation, the mainly designs goal is solves two greatly practical significance problem: how to monitor and manage DHT network traffic; how to optimize the existing network quality, and how to reduce the cost of inter-network traffic.The cache system preposed in the dissertation is composed of control server (traffic monitoring & administrating, TMA) and the cache server (P2P Cache Server, PPC). By conforming of BT protocol process, the cache system provides the transparent BT downloading cache service for local user. The experiment results indicate that it can provide excellent cache effect in DHT multi-domain network environment, and can provide great degree enhances experience of user's BT downloading.The characteristics of cache service system proposed in this dissertation include:①DHT node traffic identifying model, which proposed in this dissertation, may enhance the traffic identifying accuracy rate, and it has a better flexibility;②The bypass control model proposed in this dissertation, which can suitablly control on the unknown BT traffic which increases gradually, can increase the effectively suitable scope of cache system;③The cache system can reduce the inter-network traffic effectively and implement better cache effect through caching, hanging up, making inner peer first, and controlling on bypass traffic. |
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